Asthma is the most common chronic inflammatory respiratory disorder in children. This study was designed to assess the prevalence of asthma in 13-14-year-old adolescents in Karaj, Alborz province in Iran, using the international study of asthma and allergies in childhood (ISAAC) questionnaire. Totally 950 adolescents attending 40 schools located in 4 regions of Karaj city were enrolled in the survey. The Persian version of the ISAAC questionnaire was filled by 13-14-year-old students. Multi-stage clustered random sampling was used to divide the city of Karaj into four educational districts. Ever wheezing was reported in 22% of the individuals; 10.52% claimed to have wheeze in the last 12 months and 22.73% had during or after exercise. The experience of wheezing in the last 12 months was more prevalent among males (11.73% vs. 9.38%; p<0.05). However, having a history of asthma was higher among males (7.55% vs. 3.47%; p<0.05). History of hospitalization (60.8%), family history of asthma (49.4%), and history of food allergy (42.3%) were found to be the most frequent characteristics significantly associated with" ever wheezing" (p<0.05). The prevalence of wheezing in the last 12 months, as a major index of current asthma, was 10% which was close to the national average. However, nocturnal cough and exercise-induced wheezing were higher in Karaj compared to other cities of Iran; which could be related to the high level of air pollution in this industrial area.
Keywords: Asthma; Child; Iran; Prevalence.